Surface-colored article of copper alloy



UNITED STATES PATENT OFFICE.

rnnnstron c. MERRIMAN, on NEW HAVEN, CONNECTICUT, ASSIGNORY 'ro wincnns'rnn nnrna'rmc ARMS' 00., on NEW HAVEN, CONNECTICUT, A CORPORATION.

' sUnrAcn-coLonEnAnrIcLE on corrnn ALLOY,

No Drawing.

To all whom it may concern:

Be it known that I, THURSTON O; Manni- MAN, a citizen of the United States, resldmg at New Haven, in the count of New Haven and State of Connecticut, ave invented a new and useful Improvement in Surface- Golored Articles of Co per Alloy; and I do hereby declare the foilowing to be a full, clear, and exact description of the same.

My inventionrelates to an improved surface-colored copper alloy, the object being to produce for any available purpose, at a low cost for-production, articles of copper alloy having a durable and handsome black, or substantially black, surface color.

With these ends in view my invention consists in 'a copper alloy containing. arsenic, provided with a surface finish'of black, or

substantially black, color, and in certain details and characteristics, as will be hereinafter described and pointed out in the claims.

In carrying out in invention, I employ a copper alloy containing a small amount of arsenic. I have secured satisfactory results with an alloy consisting of parts of copper, 29 parts of zinc, and 1 part of arsenic; ut I do not limit myself to such mgredients or proportions though my present belief is that the percentages of copper and arsenic should be held around those above stated. The other ingredients will be varied according to circumstances, i. 6., as to the cost, form, character and use of the article.

An article of such characterizationthat is, characterized asan alloy of copper containing arsenic, having been thoroughly cleaned, is first immersed in an acid oxidizing bath which may be composed as follows 100 cc. water.

25 cc. nitric acid (1.42 sp. gr.)

5 gms. potassium dichromate.

In this first bath, the article is allowed to remain about five minutes at room temperature after which it is removed and thoroughly rmsed in clear cold water. The article is then subjected to an acid solution containing a. sulfid and an arsenious compound. The second bath may be composed as follows:

710 cc. waters 237 cc. hydrochloric acid (1.2 sp. gr.) 1.1 grams potassium sulfid. 1 170. grams arsenious oxid. In this second bath, the article is allowed Specification of Letters Patent.

Application filed August 5, 1919 Serial No. 315,448.

to remain about five minutes at a temperature of between 140-155 degrees F., after which the article is removed, thoroughly rinsed in cold water, dried andgiven a thin coat of light oil. The article as thus treated, will be provided with a durable and handsome surface finish of black, or substantially black, color.

I do not limit myself, as already stated,

to any particular alloys, so long as theycontain copper and arsenic, nor do I limit myself to compounding the two solutions in accordance with the formulae given, 'as the.

ingredients and their proportions may be varied as may be required by their character and strength, as well as by the specific char acter of the alloy used, nor do I limit myself to the times and temperatures stated,

as those factors will vary with the other variations suggested as falling within the purview of my invention, my present invention being characterized by producing upon the surface of an alloy containing copper and arsenic, a remarkably permanent and handsome surface finish of black, or substantiall black, color by the use of an acid oxidizm bath followed by a bath containing a su d and an arsenious salt. In my co-pending application filed August 5, 1919, Serial #315449, I have claimed the process by means of which I produce the articles hereinafter described.

I claim 1. As a new article of manufacture, an article of copper alloy containin arsenic and having a surface finish of blac or substan- THURSTON C. MERRIMAN.

Witnesses ARTHUR W. Ema, Enm S. PALMER. 

